Vehicle state estimation system

Abstract

A vibration model storage unit stores a vibration model which is made up of an unsprung part, a sprung part, a damper, a tire and a suspension spring, an actual relative distance detection unit detects an actual relative distance of the unsprung part to the sprung part, and a deviation calculation unit calculates a deviation between an estimated relative distance of the unsprung part to the sprung part that is estimated by the vibration model and the actual relative distance. An input parameter calculation unit calculates an input parameter that is inputted into the vibration model from a road surface based on the deviation calculated by the deviation calculation unit, and a vehicle state quantity calculation unit calculates a quantity of state of a vehicle by applying the input parameter to the vibration model.

Description

[0001]This application claims priority to Japanese Patent Application No. 2006-231786, filed Aug. 29, 2006, in the Japanese Patent Office. The priority application is incorporated by reference in its entirety.TECHNICAL FIELD[0002]The present disclosure relates to a vehicle state estimation system which enables a calculation of various quantities of state of a vehicle which include road surface displacement and sprung acceleration by applying an actual relative distance (a damper stroke) of a unsprung part to a sprung part of the vehicle to a vibration model of the vehicle.RELATED ART[0003]A technique is known in U.S. Pat. No. 5,987,367 in which a relative speed of an unsprung part to a sprung part of a vehicle is estimated by applying a deviation between an acceleration of the sprung part that is detected by a sensor and an acceleration of the unsprung part that is estimated to a vibration model which is made up of an unsprung part, a sprung part, a damper, a tire and a suspension s...

AI Technical Summary

Benefits of technology

[0005]Exemplary embodiments of the present invention provide a vehicle state estimation system which enable an accurate calculation of a quantity of state of a vehicle by the use of a vibration model.

[0009]One or more embodiments of the present invention may include one or more the following advantages. For example, according to the configuration of the first aspect of the present invention, the vibration model storage unit stores the vibration model which is made up of the unsprung part, the sprung part, the damper, the tire and the suspension spring, the actual relative distance detection unit detects an actual relative distance of the unsprung part to the sprung part, and the deviation calculation unit calculates a deviation between an estimated relative distance of the unsprung part to the sprung part that is estimated by the vibration model and the actual relative distance detected by the actual relative distance detection unit. The input parameter calculation unit calculates an input parameter that is inputted into the vibration model from a road surface based on the deviation calculated by the deviation calculation unit, and the vehicle state quantity calculation unit calculates a quantity of state of a vehicle by applying the input parameter calculated by the input parameter calculation unit to the vibration model. Thus, since the quantity of state of the vehicle is calculated by inputting the input parameter calculated based on the deviation between the estimated relative distance and the actual relative distance of the unsprung part to the sprung part to the vibration model, a plurality of quantities of state of the vehicle including road surface displacement can be calculated with good accuracy only by detecting the actual relative distance.

Problems solved by technology

Incidentally, since the aforesaid related-art technique handled a displacement (irregularities) of a road surface as a disturbance, the vibration model did not indicate accurately a vibrating state of a vehicle and hence had a problem that the accurate calculation of various quantities of state of a vehicle including road surface displacement was difficult.

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